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WebControl Class

.NET Framework 4

Serves as the base class that defines the methods, properties and events common to all controls in the System.Web.UI.WebControls namespace.

Inheritance Hierarchy

System.Object
  System.Web.UI.Control
    System.Web.UI.WebControls.WebControl
      More...

Namespace: System.Web.UI.WebControls
Assembly: System.Web (in System.Web.dll)

Syntax

C++

[ThemeableAttribute(true)]
public class WebControl : Control, IAttributeAccessor

ASP.NET

<asp:WebControl />

The WebControl type exposes the following members.

Constructors

	Name	Description
	WebControl()	Initializes a new instance of the WebControl class that represents a Span HTML tag.
	WebControl(HtmlTextWriterTag)	Initializes a new instance of the WebControl class using the specified HTML tag.
	WebControl(String)	Initializes a new instance of the WebControl class using the specified HTML tag.

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Properties

	Name	Description
	AccessKey	Gets or sets the access key that allows you to quickly navigate to the Web server control.
	Adapter	Gets the browser-specific adapter for the control. (Inherited from Control.)
	AppRelativeTemplateSourceDirectory	Gets or sets the application-relative virtual directory of the Page or UserControl object that contains this control. (Inherited from Control.)
	Attributes	Gets the collection of arbitrary attributes (for rendering only) that do not correspond to properties on the control.
	BackColor	Gets or sets the background color of the Web server control.
	BindingContainer	Infrastructure. Gets the control that contains this control's data binding. (Inherited from Control.)
	BorderColor	Gets or sets the border color of the Web control.
	BorderStyle	Gets or sets the border style of the Web server control.
	BorderWidth	Gets or sets the border width of the Web server control.
	ChildControlsCreated	Gets a value that indicates whether the server control's child controls have been created. (Inherited from Control.)
	ClientID	Gets the control ID for HTML markup that is generated by ASP.NET. (Inherited from Control.)
	ClientIDMode	Gets or sets the algorithm that is used to generate the value of the ClientID property. (Inherited from Control.)
	ClientIDSeparator	Gets a character value representing the separator character used in the ClientID property. (Inherited from Control.)
	Context	Gets the HttpContext object associated with the server control for the current Web request. (Inherited from Control.)
	Controls	Gets a ControlCollection object that represents the child controls for a specified server control in the UI hierarchy. (Inherited from Control.)
	ControlStyle	Gets the style of the Web server control. This property is used primarily by control developers.
	ControlStyleCreated	Gets a value indicating whether a Style object has been created for the ControlStyle property. This property is primarily used by control developers.
	CssClass	Gets or sets the Cascading Style Sheet (CSS) class rendered by the Web server control on the client.
	DataItemContainer	Gets a reference to the naming container if the naming container implements IDataItemContainer. (Inherited from Control.)
	DataKeysContainer	Gets a reference to the naming container if the naming container implements IDataKeysControl. (Inherited from Control.)
	DesignMode	Gets a value indicating whether a control is being used on a design surface. (Inherited from Control.)
	DisabledCssClass	Gets or sets the CSS class to apply to the rendered HTML element when the control is disabled.
	Enabled	Gets or sets a value indicating whether the Web server control is enabled.
	EnableTheming	Gets or sets a value indicating whether themes apply to this control. (Overrides Control.EnableTheming.)
	EnableViewState	Gets or sets a value indicating whether the server control persists its view state, and the view state of any child controls it contains, to the requesting client. (Inherited from Control.)
	Events	Gets a list of event handler delegates for the control. This property is read-only. (Inherited from Control.)
	Font	Gets the font properties associated with the Web server control.
	ForeColor	Gets or sets the foreground color (typically the color of the text) of the Web server control.
	HasAttributes	Gets a value indicating whether the control has attributes set.
	HasChildViewState	Gets a value indicating whether the current server control's child controls have any saved view-state settings. (Inherited from Control.)
	Height	Gets or sets the height of the Web server control.
	ID	Gets or sets the programmatic identifier assigned to the server control. (Inherited from Control.)
	IdSeparator	Infrastructure. Gets the character used to separate control identifiers. (Inherited from Control.)
	IsChildControlStateCleared	Gets a value indicating whether controls contained within this control have control state. (Inherited from Control.)
	IsEnabled	Gets a value indicating whether the control is enabled.
	IsTrackingViewState	Gets a value that indicates whether the server control is saving changes to its view state. (Inherited from Control.)
	IsViewStateEnabled	Gets a value indicating whether view state is enabled for this control. (Inherited from Control.)
	LoadViewStateByID	Gets a value indicating whether the control participates in loading its view state by ID instead of index. (Inherited from Control.)
	NamingContainer	Gets a reference to the server control's naming container, which creates a unique namespace for differentiating between server controls with the same Control.ID property value. (Inherited from Control.)
	Page	Gets a reference to the Page instance that contains the server control. (Inherited from Control.)
	Parent	Gets a reference to the server control's parent control in the page control hierarchy. (Inherited from Control.)
	RenderingCompatibility	Gets a value that specifies the ASP.NET version that rendered HTML will be compatible with. (Inherited from Control.)
	Site	Gets information about the container that hosts the current control when rendered on a design surface. (Inherited from Control.)
	SkinID	Gets or sets the skin to apply to the control. (Overrides Control.SkinID.)
	Style	Gets a collection of text attributes that will be rendered as a style attribute on the outer tag of the Web server control.
	SupportsDisabledAttribute	Gets a value that indicates whether the control should set the disabled attribute of the rendered HTML element to "disabled" when the control's IsEnabled property is false.
	TabIndex	Gets or sets the tab index of the Web server control.
	TagKey	Gets the HtmlTextWriterTag value that corresponds to this Web server control. This property is used primarily by control developers.
	TagName	Gets the name of the control tag. This property is used primarily by control developers.
	TemplateControl	Gets or sets a reference to the template that contains this control. (Inherited from Control.)
	TemplateSourceDirectory	Gets the virtual directory of the Page or UserControl that contains the current server control. (Inherited from Control.)
	ToolTip	Gets or sets the text displayed when the mouse pointer hovers over the Web server control.
	UniqueID	Gets the unique, hierarchically qualified identifier for the server control. (Inherited from Control.)
	ViewState	Gets a dictionary of state information that allows you to save and restore the view state of a server control across multiple requests for the same page. (Inherited from Control.)
	ViewStateIgnoresCase	Gets a value that indicates whether the StateBag object is case-insensitive. (Inherited from Control.)
	ViewStateMode	Gets or sets the view-state mode of this control. (Inherited from Control.)
	Visible	Gets or sets a value that indicates whether a server control is rendered as UI on the page. (Inherited from Control.)
	Width	Gets or sets the width of the Web server control.

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Methods

	Name	Description
	AddAttributesToRender	Adds HTML attributes and styles that need to be rendered to the specified HtmlTextWriterTag. This method is used primarily by control developers.
	AddedControl	Called after a child control is added to the Controls collection of the Control object. (Inherited from Control.)
	AddParsedSubObject	Notifies the server control that an element, either XML or HTML, was parsed, and adds the element to the server control's ControlCollection object. (Inherited from Control.)
	ApplyStyle	Copies any nonblank elements of the specified style to the Web control, overwriting any existing style elements of the control. This method is primarily used by control developers.
	ApplyStyleSheetSkin	Applies the style properties defined in the page style sheet to the control. (Inherited from Control.)
	BuildProfileTree	Infrastructure. Gathers information about the server control and delivers it to the Trace property to be displayed when tracing is enabled for the page. (Inherited from Control.)
	ClearCachedClientID	Infrastructure. Sets the cached ClientID value to null. (Inherited from Control.)
	ClearChildControlState	Deletes the control-state information for the server control's child controls. (Inherited from Control.)
	ClearChildState	Deletes the view-state and control-state information for all the server control's child controls. (Inherited from Control.)
	ClearChildViewState	Deletes the view-state information for all the server control's child controls. (Inherited from Control.)
	ClearEffectiveClientIDMode	Infrastructure. Sets the ClientIDMode property of the current control instance and of any child controls to Inherit. (Inherited from Control.)
	CopyBaseAttributes	Copies the properties not encapsulated by the Style object from the specified Web server control to the Web server control that this method is called from. This method is used primarily by control developers.
	CreateChildControls	Called by the ASP.NET page framework to notify server controls that use composition-based implementation to create any child controls they contain in preparation for posting back or rendering. (Inherited from Control.)
	CreateControlCollection	Creates a new ControlCollection object to hold the child controls (both literal and server) of the server control. (Inherited from Control.)
	CreateControlStyle	Creates the style object that is used internally by the WebControl class to implement all style related properties. This method is used primarily by control developers.
	DataBind()	Binds a data source to the invoked server control and all its child controls. (Inherited from Control.)
	DataBind(Boolean)	Binds a data source to the invoked server control and all its child controls with an option to raise the DataBinding event. (Inherited from Control.)
	DataBindChildren	Binds a data source to the server control's child controls. (Inherited from Control.)
	Dispose	Enables a server control to perform final clean up before it is released from memory. (Inherited from Control.)
	EnsureChildControls	Determines whether the server control contains child controls. If it does not, it creates child controls. (Inherited from Control.)
	EnsureID	Creates an identifier for controls that do not have an identifier assigned. (Inherited from Control.)
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	FindControl(String)	Searches the current naming container for a server control with the specified id parameter. (Inherited from Control.)
	FindControl(String, Int32)	Infrastructure. Searches the current naming container for a server control with the specified id and an integer, specified in the pathOffset parameter, which aids in the search. You should not override this version of the FindControl method. (Inherited from Control.)
	Focus	Sets input focus to a control. (Inherited from Control.)
	GetDesignModeState	Infrastructure. Gets design-time data for a control. (Inherited from Control.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetRouteUrl(Object)	Gets the URL that corresponds to a set of route parameters. (Inherited from Control.)
	GetRouteUrl(RouteValueDictionary)	Gets the URL that corresponds to a set of route parameters. (Inherited from Control.)
	GetRouteUrl(String, Object)	Gets the URL that corresponds to a set of route parameters and a route name. (Inherited from Control.)
	GetRouteUrl(String, RouteValueDictionary)	Gets the URL that corresponds to a set of route parameters and a route name. (Inherited from Control.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	GetUniqueIDRelativeTo	Returns the prefixed portion of the UniqueID property of the specified control. (Inherited from Control.)
	HasControls	Determines if the server control contains any child controls. (Inherited from Control.)
	HasEvents	Returns a value indicating whether events are registered for the control or any child controls. (Inherited from Control.)
	IsLiteralContent	Infrastructure. Determines if the server control holds only literal content. (Inherited from Control.)
	LoadControlState	Restores control-state information from a previous page request that was saved by the SaveControlState method. (Inherited from Control.)
	LoadViewState	Restores view-state information from a previous request that was saved with the SaveViewState method. (Overrides Control.LoadViewState(Object).)
	MapPathSecure	Retrieves the physical path that a virtual path, either absolute or relative, maps to. (Inherited from Control.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	MergeStyle	Copies any nonblank elements of the specified style to the Web control, but will not overwrite any existing style elements of the control. This method is used primarily by control developers.
	OnBubbleEvent	Determines whether the event for the server control is passed up the page's UI server control hierarchy. (Inherited from Control.)
	OnDataBinding	Raises the DataBinding event. (Inherited from Control.)
	OnInit	Raises the Init event. (Inherited from Control.)
	OnLoad	Raises the Load event. (Inherited from Control.)
	OnPreRender	Raises the PreRender event. (Inherited from Control.)
	OnUnload	Raises the Unload event. (Inherited from Control.)
	OpenFile	Gets a Stream used to read a file. (Inherited from Control.)
	RaiseBubbleEvent	Assigns any sources of the event and its information to the control's parent. (Inherited from Control.)
	RemovedControl	Called after a child control is removed from the Controls collection of the Control object. (Inherited from Control.)
	Render	Renders the control to the specified HTML writer. (Overrides Control.Render(HtmlTextWriter).)
	RenderBeginTag	Renders the HTML opening tag of the control to the specified writer. This method is used primarily by control developers.
	RenderChildren	Outputs the content of a server control's children to a provided HtmlTextWriter object, which writes the content to be rendered on the client. (Inherited from Control.)
	RenderContents	Renders the contents of the control to the specified writer. This method is used primarily by control developers.
	RenderControl(HtmlTextWriter)	Outputs server control content to a provided HtmlTextWriter object and stores tracing information about the control if tracing is enabled. (Inherited from Control.)
	RenderControl(HtmlTextWriter, ControlAdapter)	Outputs server control content to a provided HtmlTextWriter object using a provided ControlAdapter object. (Inherited from Control.)
	RenderEndTag	Renders the HTML closing tag of the control into the specified writer. This method is used primarily by control developers.
	ResolveAdapter	Gets the control adapter responsible for rendering the specified control. (Inherited from Control.)
	ResolveClientUrl	Gets a URL that can be used by the browser. (Inherited from Control.)
	ResolveUrl	Converts a URL into one that is usable on the requesting client. (Inherited from Control.)
	SaveControlState	Saves any server control state changes that have occurred since the time the page was posted back to the server. (Inherited from Control.)
	SaveViewState	Saves any state that was modified after the TrackViewState method was invoked. (Overrides Control.SaveViewState().)
	SetDesignModeState	Sets design-time data for a control. (Inherited from Control.)
	SetRenderMethodDelegate	Infrastructure. Assigns an event handler delegate to render the server control and its content into its parent control. (Inherited from Control.)
	ToString	Returns a string that represents the current object. (Inherited from Object.)
	TrackViewState	Causes the control to track changes to its view state so they can be stored in the object's ViewState property. (Overrides Control.TrackViewState().)

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Events

	Name	Description
	DataBinding	Occurs when the server control binds to a data source. (Inherited from Control.)
	Disposed	Occurs when a server control is released from memory, which is the last stage of the server control lifecycle when an ASP.NET page is requested. (Inherited from Control.)
	Init	Occurs when the server control is initialized, which is the first step in its lifecycle. (Inherited from Control.)
	Load	Occurs when the server control is loaded into the Page object. (Inherited from Control.)
	PreRender	Occurs after the Control object is loaded but prior to rendering. (Inherited from Control.)
	Unload	Occurs when the server control is unloaded from memory. (Inherited from Control.)

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Extension Methods

	Name	Description
	FindDataSourceControl	Returns the data source that is associated with the data control for the specified control. (Defined by DynamicDataExtensions.)
	FindFieldTemplate	Returns the field template for the specified column in the specified control's naming container. (Defined by DynamicDataExtensions.)
	FindMetaTable	Returns the metatable object for the containing data control. (Defined by DynamicDataExtensions.)

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Explicit Interface Implementations

	Name	Description
	IAttributeAccessor.GetAttribute	Infrastructure. Gets an attribute of the Web control with the specified name.
	IAttributeAccessor.SetAttribute	Sets an attribute of the Web control to the specified name and value.
	IControlBuilderAccessor.ControlBuilder	For a description of this member, see IControlBuilderAccessor.ControlBuilder. (Inherited from Control.)
	IControlDesignerAccessor.GetDesignModeState	For a description of this member, see IControlDesignerAccessor.GetDesignModeState. (Inherited from Control.)
	IControlDesignerAccessor.SetDesignModeState	For a description of this member, see IControlDesignerAccessor.SetDesignModeState. (Inherited from Control.)
	IControlDesignerAccessor.SetOwnerControl	Infrastructure. For a description of this member, see IControlDesignerAccessor.SetOwnerControl. (Inherited from Control.)
	IControlDesignerAccessor.UserData	For a description of this member, see IControlDesignerAccessor.UserData. (Inherited from Control.)
	IDataBindingsAccessor.DataBindings	For a description of this member, see IDataBindingsAccessor.DataBindings. (Inherited from Control.)
	IDataBindingsAccessor.HasDataBindings	For a description of this member, see IDataBindingsAccessor.HasDataBindings. (Inherited from Control.)
	IExpressionsAccessor.Expressions	For a description of this member, see IExpressionsAccessor.Expressions. (Inherited from Control.)
	IExpressionsAccessor.HasExpressions	For a description of this member, see IExpressionsAccessor.HasExpressions. (Inherited from Control.)
	IParserAccessor.AddParsedSubObject	For a description of this member, see IParserAccessor.AddParsedSubObject. (Inherited from Control.)

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Remarks

The WebControl class provides the properties, methods, and events that are common to all Web server controls. You can control the appearance and behavior of a Web server control by setting properties defined in this class. For example, the background color and font color of a control are controlled by using the BackColor and ForeColor properties, respectively. On controls that can display a border, you can control the border width, the border style, and the border color by setting the BorderWidth, BorderStyle, and BorderColor properties. The size of a Web server control can be specified by using the Height and Width properties.

The behavior of the control can be specified by setting certain properties. You can enable and disable a control by setting the Enabled property. The place of the control in the tab order is controlled by setting the TabIndex property. You can specify a ToolTip for the control by setting the ToolTip property.

Note
Not all controls support every property defined in this class. For specific information about whether a property is supported, see the documentation for the specific control.

Note
Some properties in this class render differently, depending on the browser. Some properties do not render at all, while others render, but have no effect. The TagWriter property of the HttpBrowserCapabilities object determines the way in which a Web server control renders. For browsers that support HTML 4.0, the TagWriter property will contain a regular HttpBrowserCapabilities object, and most properties will be rendered using HTML 4.0 style attributes. Browsers that are not known to support HTML 4.0 will use the Html32TextWriter object. This will automatically map the style attributes to any relevant HTML 3.2 tag attributes. In some cases, such as with the ForeColor property, the style attributes will be converted into additional tags, such as <font> tags. In some cases, there will be no mapping performed. For specific information about how a property is rendered in different browsers, see the documentation for the specific property.

Note

Some properties in this class render differently, depending on the browser. Some properties do not render at all, while others render, but have no effect. The TagWriter property of the HttpBrowserCapabilities object determines the way in which a Web server control renders. For browsers that support HTML 4.0, the TagWriter property will contain a regular HttpBrowserCapabilities object, and most properties will be rendered using HTML 4.0 style attributes. Browsers that are not known to support HTML 4.0 will use the Html32TextWriter object. This will automatically map the style attributes to any relevant HTML 3.2 tag attributes. In some cases, such as with the ForeColor property, the style attributes will be converted into additional tags, such as <font> tags. In some cases, there will be no mapping performed. For specific information about how a property is rendered in different browsers, see the documentation for the specific property.

For a list of initial property values for an instance of WebControl, see the WebControl constructor.

Topic	Location
Developing Custom Data-Bound Web Server Controls for ASP.NET 1.1	Authoring ASP.NET Controls
Walkthrough: Creating a Basic Control Designer for an ASP.NET Web Server Control	Authoring ASP.NET Controls
Walkthrough: Developing and Using a Custom Server Control	Authoring ASP.NET Controls
Walkthrough: Creating a Custom Data-Bound ASP.NET Web Control for ASP.NET 1.1	Authoring ASP.NET Controls
How to: Set ASP.NET Server Control Style Properties Using ASP.NET Syntax	Building ASP .NET Web Applications
Walkthrough: Creating a Basic Control Designer for an ASP.NET Web Server Control	Authoring ASP.NET Controls
Walkthrough: Developing and Using a Custom Server Control	Authoring ASP.NET Controls
Developing Custom Data-Bound Web Server Controls for ASP.NET 1.1	Authoring ASP.NET Controls
Walkthrough: Creating a Custom Data-Bound ASP.NET Web Control for ASP.NET 1.1	Authoring ASP.NET Controls
How to: Set ASP.NET Server Control Style Properties Using ASP.NET Syntax	Building ASP .NET Web Applications
Developing Custom Data-Bound Web Server Controls for ASP.NET 1.1	Building ASP .NET Web Applications in Visual Studio
Walkthrough: Creating a Custom Data-Bound ASP.NET Web Control for ASP.NET 1.1	Building ASP .NET Web Applications in Visual Studio

Examples


namespace ControlTest 
{
   using System;
   using System.Web.UI;
   using System.Web.UI.WebControls;

   // Renders the following HTML: 
   // <span onclick="alert('Hello');" style="color:Red;">Custom Contents</span>

   public class MyWebControl: WebControl {

      public MyWebControl() : base(HtmlTextWriterTag.Span) 
      { }

      [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")] 
      protected override void AddAttributesToRender(HtmlTextWriter writer) 
      {

         writer.AddAttribute(HtmlTextWriterAttribute.Onclick, "alert('Hello');");
         writer.AddStyleAttribute(HtmlTextWriterStyle.Color, "Red");
         base.AddAttributesToRender(writer);

      }

      [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name="FullTrust")] 
      protected override void RenderContents(HtmlTextWriter writer) 
      {
         writer.Write("Custom Contents");
         base.RenderContents(writer);
      }
   }
}

Version Information

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.